NEW ORLEANS — New England quarterback Tony Eason missed practice Friday with what was described as a "mild viral illness," but the Patriot team doctor said he was optimistic that Eason would be ready for Sunday's Super Bowl.

Coach Raymond Berry said Eason became ill about 10 p.m. Thursday night during a meeting with quarterbacks and receivers.

Veteran Steve Grogan, just activated after missing seven games with a broken leg and a knee injury, took all the snaps at practice with a brace on his knee. Berry said Grogan would start if Eason wasn't ready.

"It looks like he has mild viral illness," Dr. Bertram Zarins, the Patriots' team physician, said of Eason. "We kept him out of practice to give him some rest. . . . At this point, it doesn't look serious."

Zarins said it was a "generalized viral illness."

Berry wasn't so optimistic. "I don't know how serious it is right now," he said. "There's the possibility it could be a whopper. They don't really know. . . ."

As for Butler, Bear trainer Fred Caito said he expected the virus to last between 16 and 20 hours. Coach Mike Ditka said Butler would kick today when the Bears practice in the Superdome.